Thermostats in your L-134

[Deleted]

Good day!, One issue with the L-134 that comes up most often is the thermostat and replacement, I would like to offer some help here as well as how to make your own gasket very easily.
Often after replacing a t stat I often see on forums is, "I just installed a new T stat and now it pushes coolant out the radiator cap". Three things most often cause this.

1) Overfilling the radiator, do not fill to the top leave a little room for the coolant to expand as it heats up, if not it will push it out the overflow.

2) Your engine is airlocked, or as you fill the coolant it can not push the air in the block past the t stat, so after your engine is running there is no coolant touching the t stat and it is not able to open and the coolant will boil in the block until the steam gets the thermostat hot enough to open, while this is happening the steam pressure back feeds the radiator and pushes coolant out the overflow. This causes the installer to think the new t stat is bad and installed another only to face the same issue. this is easily avoided by drilling a small hole in the new t stat, allowing the air to vent through the t stat into the top of the radiator.

3) A bad head gasket, cracked head or block, all common on a 60-70 year old engine.

The more you spend on a thermostat the better the quality, high end models have a vent hole in them, most parts stores sell the cheaper grade, in the below picture there is a vintage t stat I removed from a Supersonic head, notice the vent hole in it.


Next is a t stat I removed from a QSB Cummins engine at work, at the tip of the screwdriver you will see a rivet in the vent hole, this is common on a high end t stat it will allow the air to pass but limit the coolant to a very small amount.

Next is a proper 160 degree stat installed in the housing, with a vent hole drilled in it (two will not hurt either), note the tin spacer for the t stat you will need one, very cheap, this one I purchased from a vendor for $3.
.

Lee

[Haines Garage]

Sir Leemeister....all I can say is Thank You For Posting.
This topic is another one, Most Important, and most overlooked.
You have some serious skills and knowledge my friend....
Thank you again for sharing it with us.

[Deleted]

Haines, thank you, and watch this as I will be adding to it. I had trouble with the gasket part and lost it in internet space, will redo later .

Lee

[athawk11]

Excellent information. I always wondered where I should drill a hole if and when it's time for a new thermostat.

Tim

[Haines Garage]

Hey Captain! What size hole are we drilling?

[Deleted]

One 1/8 inch hole is plenty.

[Deleted]

Just bubbling this informative post back to the top of our minds. There is a lot of great stuff here...and it might be useful to someone learning about thermostats around here.

[Deleted]

The way to cool a engine is air flow, or cooland flow. Thermostats manage the coolant flow and meter it to the radiator. A engine needs temperature to burn off the by produsts of combustion. Too cold and it sludges with the water and byproducts. Too hot and it cracks things. Your Jeep's original thermostat was a bellows type that expanded and contracted with temp. change and opened and closed a flapper. The flapper had a small hole in it to equalize the fluid on both sides of the thermostat. Speeding up or slowing the flow through the radiator will allow the exchange of the heat produced by the engine and uses air through the radiator fins to cool it. So, too fast through the radiator will not cool the fluid. No air through the radiator , it will not cool. A plugged set of tubes in the radiator = no cool. Fan shrouds, and letting air out of the engine bay all help with air flow through the radiator. The air dams and felt seals make the air go through the radiator instead of around it. All this stuff was engineered to cool your engine when it was designed and produced. If you change the parameters, you will get a lesson about it. Race cars running wide open actually use a plate with a hole in it to meter the water flow and do not use a thermostat. Running with no thermostat usually will cause it to run too cool or too hot. Depends on the condition of the radiator core and air ducting. Get it now? Oil

[jeffwho]

Well, "Script-F" me, there it is.

Lee, great tutorial. Pictures help us rookies, of course.
Oilly, your explanation makes perfect sense, and I appreciate you hammering that out. I understand the concept, but I really "get it" after that! Thanks!
Moosey, I couldn't pay you enough to compensate you for your patience. If you change your phone number, I'd understand.

Imagine if you will, a guy as mechanically inclined as a stone "reading up on topics of interest related to current events" and finding two TOTALLY different pieces of advice in regard to said situation. Sometimes, if you're really careful, you can find a third source, and follow that advice along the lines of "go'head and piss on that 'letric fence, cain't hurt ya 'tall" results.

1. The guy who suggested that thermostats are not necessary at all for "casual driving in areas of moderate temps year round"
2. The "Member, Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician" on G503 suggests that holes in thermostats are not needed.
3. Lee's tutorial with detailed pictures on drilling 1/8" hole in thermostat

Here's the conundrum: Do I stop asking dumb questions, or press on trying to learn all on me own? All I know for sure is that damned fence HURTS, and it seems ta gets ME every time.
ZZZZAPPP!!!!!!!! LOL

[Deleted]

THERE IS NO SUCH THING AS A DUMB QUESTION! I was a rookie once myself. I try to learn something new about our Jeeps every day. I've been actively in and around Jeeps for nearly nineteen years. I do extensive research on a daily basis. I'm still a rookie. I still learn something new everyday. From time to time an expert will appear and expound on his technical knowledge and expertise. He will offer "sage" tidbits. For a while. He will nearly as quickly disappear when he learns he doesn't know everything. There is no limit to the questions you may ask. Just remember. It's the question you knew to ask, and didn't, that will earn you that bite in the butt. If you don't understand an answer, ask again and request clarification. There's no shame in admitting you were wrong either.

[Deleted]

If you want a exercise in heating and cooling problems, buy a MGA made in England. It must never get hot over there. Over here, the design is woefully inadequate. I spend a week fooling around trying to cool the thing. Thermostats, shrouds, wetter water, extra fans, on and on. I saw where racers had removed every other grill slat, raised the back of the hood up to let air out of the engine bay. Louvered hoods. I even had a extra row of core installed in the radiator. What amazed me was one day we happened to have the grill out of the car up front, and took it for a drive. It never moved off 180 on the temp. gauge. Put the grill back in and immediately drove the same route , same day, 195!!!!!!!!!!!! That grill is actually deflecting air away from the radiator. Lots of interesting things to learn about cooling a engine huh? Oil

[Deleted]

Jeff, I second Scout!!!! Nobody knows it all, all of us are still learning in someway shape or form. The good thing about these forums is the free exchange of information that wasn't possible a few short years ago. Everyone has different experiences and opinions to bring to the table. The bad side is anybody with enough time and a keyboard can become a self-proclaimed expert on things.... Give bad advice often and forceful enough, some people will start to believe they are an "expert". I wish I had the likes of Lee, Oily, Hawky, BoBo and the rest when I was first building my jeep. It would've saved me tons of money and aggravation... School of hard knocks isn't frigging cheap....

[Haines Garage]

I third the ScoutPilot. That's what we do, help each other out! Then you can pass on to the next worthy cause. Notice I said worthy. I am not talking about the same dumbasses who ask silly shit because they are too lazy to read a manual. Those gurus out there in cyberland....they are all full of shit!!! Trust me, I know a lot of them.
Now....
What oil should I use in my transmission?

[Deleted]

Dextron III / Mercon. (Just kidddin' woods-watchers, lol)

Back on topic... Anybody who says a L134 can't airlock and overheat is F.O.S!

Happened to me, it will heat up in a danm hurry.... In hindsight, that's was probably what lead to my broken rings a year or so ago......



Of course, I drilled two holes.... Maybe it was overkill, takes forever to warm up in the winter....

[Deleted]

On the flip side of of the thermostat life...how about this? Seven years ago when I first installed my thermostat during my GPW rebuild, I did not drill a hole. My thermostat did not have the hole, either. I didn't even know about the possible reprocussions of not having a hole. During that time frame, I drove my jeep and never had any issues.

When I flushed my cooling system a few weeks ago, I replaced my thermostat and drilled a hole prior to installation. (Just to be safe)

So, there is a chance that detard's jeep will be fine. What symptoms should he look for otherwise: excessive temps?

[Deleted]

It's simple if your Jeep overheats. Radiator has to be clean inside and open tubes, shroud, correct thermostat setup, distributor timing and advance unit working and not going too far advance from worn springs, 4 # radiator cap that seals in the neck, fuel mixture not too lean, no cracks causing the block to overpressure and spit out the antifreeze, heat riser functional, no vacuum leaks causing a lean mixture, exhaust system not plugged up, block not full of crap, and last but not least, you are not hauling too many fat chicks to correct the leaning to one side! Oilly

[jeffwho]

Well, we shall see. The only certainty is that even fat chicks won't ride with me, so that lean will just stay as it is.
Last night I couldn't get the durn thing to crank, so Dopey might not be coming home today afterall.

[Deleted]

In my opinion, the only time a thermostat will "airlock" is when filling up after draining. It more than likely won't happen, but it can, that's all.

[athawk11]

May 15, 2015 11:01:07 GMT -5 @gmcjr said:

In my opinion, the only time a thermostat will "airlock" is when filling up after draining. It more than likely won't happen, but it can, that's all.

I concur.

Some added incite... I knew nothing of the rules pertaining to the drilling of the thermos. I completely drained and flushed the engine block and radiator on the OD Willys. When I fired it all back up, I never had an airlock issue. But after reading many stories of this phenomenon, I understood the possibility. So, I drill the whole, because it all but guarantees this won't happen.

Per others comments...Without the help of the men and women on these forums, I would have never taken on the challenge of a Willys Jeep. You all have set my life on a new path. And it's a path I really enjoy. So...I thank all of you.

Tim

[Deleted]

Hawky, not only advice, but darn good friendship and time behind the wheel together on the trail. Now that's fun. Oil

[Deleted]

Very inexpensive insurance.

[jeffwho]

Felt great to drive Lucille today - "F script" work, I had better ideas. Ran some errands, got more time on my hand crank, and got over the Goat Farm for some tips. Talked cheese with Moosey about my mind-melding with the cooling system in my jeep. Poor Dopey is going to miss the Goat Coach, but at some point in future I'll see the guts of a tranny and WOW how much more can I ask?